Reconfigurable intelligent surfaces (RIS) have been presented as a solution to realize the concept of smart radio environments, wherein uninterrupted coverage and extremely high quality of service can be ensured. In this paper, assuming that multiple RIS are deployed in the propagation environment, the performance of a cascaded RIS network affected by imperfect phase estimation is evaluated. Specifically, we derive closed-form expressions for the outage probability, the ergodic capacity and the average symbol error probability that can be utilized to evaluate the coverage of the proposed network, as well as the average capacity and the data transmission accuracy. Finally, we validate the derived expressions through simulations and show that by choosing the number of the participating RIS correctly, a cascaded RIS network can outperform a single RIS aided system and extend the network's coverage efficiently.

翻译：作为实现智能无线电环境概念的一种解决办法,人们提出了可重新配置的智能表面(RIS)作为实现智能无线电环境概念的一种解决办法,在智能无线电环境概念中,可以确保不间断的覆盖范围和极高的服务质量;在本文中,假设在传播环境中部署多个RIS,将评估受不完善阶段估计影响的级联RIS网络的性能;具体地说,我们得出了闭式表达方式,以表示出出断裂概率、垂直容量和平均符号误差概率,可用于评价拟议网络的覆盖范围以及平均容量和数据传输准确性;最后,我们通过模拟验证衍生的表达方式,并表明通过正确选择参与的RIS的数量,级联的RIS网络可以超越单一的RIS辅助系统,并有效扩大网络的覆盖范围。